Alessian Order is an item set found in boxes bought from a merchant in Vlastarus or as quest rewards. Pieces are Aldmeri Dominion, Daggerfall Covenant, or Ebonheart Pact Style in Heavy Armor.
2 items: Adds 34-2975 Physical Resistance
3 items: Adds 34-2975 Spell Resistance
4 items: Adds 14-1206 Maximum Health
5 items: Increase your Health Recovery by 1% of your sum total Physical Resistance and Spell Resistance.; current Bonus Health Recovery: 0.
The set consists of heavy armor and jewelry in all slots, as well as weapons and shields of all types.